<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    html,
    body {
      margin: 0;
      padding: 0;
    }
    .container {
      height: 200px;
      border: 2px solid #000;
      display: flex; /*弹性布局*/
      justify-content: space-between; /*两端对齐*/
    }
    .container .left {
      width: 300px;
      background-color: tomato;
    }
    .container .right {
      display: flex; /*弹性布局，这样子元素没有添加高度时，会和父元素一样高*/
    }
    .container .right .item1 {
      width: 200px;
      background-color: pink;
    }
    .container .right .item2 {
      width: 100px;
      background-color: skyblue;
    }
  </style>
  <body>
    <div class="container">
      <div class="left"></div>
      <div class="right">
        <div class="item1"></div>
        <div class="item2"></div>
      </div>
    </div>
  </body>
</html>